Sudden acne?

Out of nowhere my face is breaking out and I'm just wondering what is the best thing for acne or pimples? I have always had clear skin so this is all new to me but I just moved to Texas from Arkansas and I'm also sweating more and could be stress. Just wondering what can clear this up. It's not like big pimples just small red bumps on my forhead and nose area. :/ thank you!